Ehlers-Danlos syndrome is a group of disorders that affect connective tissues, which are tissues that support the skin, bones, blood vessels, and other organs. Defects in connective tissues cause the signs and symptoms of Ehlers-Danlos syndrome, which vary from mildly loose joints to life-threatening complications.
There are 6 recognized types of Ehlers-Danlos syndrome:
Other forms of the condition may exist, but they have been reported only in single families or are not well characterized.
Mutations in the ADAMTS2, COL1A1, COL1A2, COL3A1, COL5A1, COL5A2, PLOD1, and TNXB genes cause Ehlers-Danlos syndrome.
Although it is difficult to estimate the overall frequency of Ehlers-Danlos syndrome, the combined prevalence of all types of this condition may be about 1 in 5,000 individuals worldwide. The hypermobility and classic forms are most common; the hypermobility type may affect as many as 1 in 10,000 to 15,000 people, while the classic type probably occurs in 1 in 20,000 to 40,000 people.
Other forms of Ehlers-Danlos syndrome are very rare. About 30 cases of the arthrochalasia type and fewer than 60 cases of the kyphoscoliosis type have been reported worldwide. About a dozen infants and children with the dermatosparaxis type have been described. The vascular type is also rare; estimates vary widely, but the condition may affect about 1 in 250,000 people.
An unusually large range of joint movement (hypermobility) occurs with most forms of Ehlers-Danlos syndrome, particularly the hypermobility type. Infants with hypermobile joints often appear to have weak muscle tone, which can delay the development of motor skills such as sitting, standing, and walking. The loose joints are unstable and prone to dislocation, chronic pain, and early-onset arthritis. Dislocations involving both hips are a characteristic finding in infants with the arthrochalasia type of Ehlers-Danlos syndrome.
Many people with Ehlers-Danlos syndrome have soft, velvety skin that is highly elastic (stretchy) and fragile. Affected individuals tend to bruise easily, and some types of the condition also cause abnormal scarring. People with the classic form of Ehlers-Danlos syndrome experience wounds that split open with little bleeding and leave scars that widen over time to create characteristic shallow "cigarette paper" scars. The dermatosparaxis type of the disorder is characterized by skin that sags and wrinkles. Extra folds of skin may be present as affected children get older.
Some forms of Ehlers-Danlos syndrome, notably the vascular and kyphoscoliosis types, can involve serious and potentially life-threatening complications.
There is no cure for Ehlers-Danlos syndrome, and treatment is supportive. Treatment includes:
Anyone who has the condition is advised to take extra caution and observe special practices to avoid injury.